TCP

• http://articles.techrepublic.com.com/5100-10878_11-1050878.html -- "TCP/IP options for high-performance data transmission"
• http://www.ussg.iu.edu/hypermail/linux/kernel/0102.0/0943.html -- LKML thread, "TCP_NOPUSH on FreeBSD, TCP_CORK on Linux"
• http://www.irbs.net/internet/postfix/0707/1097.html -- postfix thread, "dkim-milter signing terribly slow with Postfix, but not with sendmail"
  • This becomes: "TCP_NODELAY, TCP_CORK, TCP_NOPUSH, etc (was: dkim-milter signing terribly slow...)"

Portable APIs

• TCP_NODELAY: Disable Nagle's algorithm (coalescing of small packets until an ACK is received or a retransmission triggered). See the Linux APIs page for interactions with TCP_CORK on that platform.

Tuning

TCP auto-tuning on Linux

• netdev 2009-03-11, "TCP rx window autotuning harmful at LAN context"
• The Pittsburgh Supercomputing Center's Linux TCP notes

TCP auto-tuning on FreeBSD

• Finally introduced in [FreeBSD 7.2] by Andre Oppermann:

With TCP send buffer auto scaling and the default values below it supports 20Mbit/s at 100ms and 10Mbit/s at 200ms. Both read and write buffer are auto-sized.

See also

• Linux's TCP socket options
• FreeBSD's TCP socket options
• TCP and Linux' Pluggable Congestion Control Algorithms, a 2007 Linux Gazette article by René Pfeiffer